To evaluate azithromycin tear concentrations after one drop of azithromycin eyedrops (2.5ml/25mg) in healthy volunteers.

In this randomized, open, single-center study, 42 healthy volunteers will receive one drop of azithromycin into each eye. Azithromycin tear concentrations will be measured by LC-MS/MS at seven time points for 24 hours. Tolerability is evaluated.

Inclusion Criteria:

• 18 to 45 years old, male or female;
• BMI in the range of 19 to 24;
• eyes corrected visual acuity should be ≥ 1.0, intraocular pressure, slit lamp and fundus examination were normal, tear secretion function is normal;
• Good compliance and voluntarily signed consent.

Exclusion Criteria:

• Have eye disease or systemic disease;
• physical examination, laboratory tests, ECG and chest X-ray examination abnormalities and has clinical significance;
• HBsAg, anti-HCV, anti-HIV and TPPA positive;
• those who used eye drops two weeks before the test and who used any dosage form of azithromycin;
• known to azithromycin or macrolide-related varieties of allergies or serious adverse reactions;
• need to wear contact lenses during the test;
• history of internal surgery or laser surgery history;
• participated in other drug clinical trials in the past three months;
• pregnant women and lactating women, or in the growth period without taking effective contraceptive measures, menstrual period women;
• mental illness or alcohol, history of drug abuse or inability to collaborate;
• Any other circumstances that the investigators consider are unfit to participate in this study.